Introduction: Hovercraft 3000
Ever wanted to glide by your friends, sipping your favorite boba or Starbucks frappe? Ever wanted to be able to rev up your engine like those guys with mustangs and Porsches? Ever wanted to not walk home after work or school? HOVERCRAFT3000 is here to give you all that and more!!
I have always wanted to ride a hovercraft and been fascinated with making my own vehicle since middle school. When I was deliberating on what project I would be doing for MakerFaire, it occurred to me that this would be the perfect platform to experiment with such a project especially since our teacher Mrs. Berbawy, the founder of Berbawy Makers, which is a group that exists to provide opportunities for students at Irvington High School to explore their interests in engineering through making, had generously offered to sponsor the project.
Well now with any further a-do lets dive into the make process!!
Step 1: Design for Base and Cut Base
I spent a lot of time figuring out what kind of base I would use for my hovercraft. Most the modules that were on YouTube used a circular base, much like that of a UFO. Although I understand that having a circular base would essentially make the entire project much easier in terms of design.
A more circular design would ensure a more uniform distribution of air and would decrease the chances of any side collapsing due to imbalance of weight. It would on the other hand reduce workable space and wouldn't leave enough space for a propeller or proper seating. The rectangular design would provide a lot of workable and would theoretically make it possible to fit two people at the same time. Despite these advantages a rectangular hovercraft would compromise the crafts aerodynamic shape whilst adding extra weight which in turn would increase the cost of making the hovercraft. The design that I finally chose for the hovercraft incorporates the pros of both of the previous ideas whilst still being feasible. It allows us to maximize the efficiency of the craft without adding too much weight, while still holding a sort of aesthetic appeal.I used a 4' x 6' x 0.484'' piece of ply wood and then cut it according to the design using a wood cutter in a wood shop.
Step 2: Cutting Air Hole
I cut the hole into the hovercraft board using the following materials:-
- DeWalt DC7010 3/8" (10mm) cordless drill/ driver
- 2' 1/2" DeWalt circle cutter
- 2 cinder blocks
- safety goggles
- 1/4" drill bit
Step 3: Cutting and Attaching Tarp
I used 8' by 10' of Bluehawk heavy duty silver brown tarp to make the skirt for he hovercraft. The complete process can be described in the following steps:-
- Lay out the tarp and place the board on top of the the tarp at approximately the center.
- Cut a 1 feet border all around the hovercraft
- Fold tarp onto the hovercraft such that approximately 1" to 1 1/2" of tarp is on the plywood
- Use the staple gun to staple the tarp onto the tarp
- Seal the tarp onto the board using 2 layers of duct tape
IMPORTANT NOTE: make sure you have a responsible adult present while using the staple gun to avoid injury
Step 4: Attaching Board to the Bottom of Hover Craft
I used 2' x 1' x 0.125" of Birchwood for the bottom of the hovercraft. I designed the base using Adobe Illustrator and laser cut the wood using Universal Laser Systems at standard vector setting, normal focus setting, and normal power setting.
I then drilled the board onto my original hovercraft base and then duct taped to ensure that there is no leakage
Step 5: Adding Air Holes at the Bottom
The size of the air holes at the bottom of the hovercraft must be in proportion with the entire size and weight for the hovercraft. We must also take into consideration the number of holes. The current estimated load it ca take is approximated to be around 180 lbs - 200 lbs, along with this the size of the board is 4' x 6' and the current airflow is about 540 CFM. Taking all these factors into consideration I decided on 6" diameter for the hovercraft holes and the number of holes being 10.
After Cutting the holes I discovered that my input of 540 CFM is not sufficient to the sustain the output of the air holes, at that point I redesigned the holes and covered half of the half way to adjust for the discrepancy.
NOTE: Although here I have used air holes of 6" I would recommend a smaller diameter of about 4" - 5"
Step 6: Test #1
In my first test for a working hovercraft, some problems that I discovered are:-
1) Drag (as I had suspected)
2) Sturdiness (finding center of mass)
Mostly the hovercraft did pretty well on its first test run and no leakage was observed. I would certainly say it was a success.
Links to my first 2 tests are:-
Step 7: Fixing Drag
After the first test of my hovercraft, I realized one of the main things I would need to fix for my hovercraft is drag.
After having a long and to be a brutally honest tiresome discussion with some of my more advanced fellow classmates, I decided to take up their suggestion to completely cut out the air holes at the bottom of the hovercraft. They argued it would increase the output and "consequently increase the liftoff from the ground, enabling it to 'hover' more efficiently." My main concern regarding this was that.
Increase in the output of air = Decrease of air pressure inside the system
I suspect the problem is not regarding the holes at the bottom of the hovercraft but rather is the problem of decreased air flow. The current leaf blower that I have which is quite powerful and maintains a 540 CFM output. Due to the enlarged air hole, we are going to need increased pressure to maintain inflation while decreasing the drag. I decided that I would need to get another leaf blower so that their combined air pressure would be sufficient to decrease drag.
Step 8: CAD for Connector and Adding New Leaf Blower
I got a cheap leaf blower Best Partner 18 volt 130 mph Lithium-Ion Cordless. It weighs 3.67 lbs and would solve the problem of decreased airflow in the hovercraft.
I made the connector using Adobe Illustrator and 3D printed it using Lulzbot Tav with the setting as shown in the picture.
Step 9: FINAL TEST
I was finally able to put together my hovercraft and test its ability to hold the target weight and glide. I tested the craft with 4 students from my class in differing weight classes. They weighed 80 lbs, 120 lbs, 155 lbs, and 180 lbs. The hovercraft glided surprising well.
The links to the videos of the tests can be found below:-